13 research outputs found
Time-Resolved Diffusing Wave Spectroscopy for selected photon paths beyond 300 transport mean free paths
This paper is devoted to the theoretical and experimental demonstration of
the possibility to perform time-resolved diffusing wave spectroscopy: we
successfully registered field fluctuations for selected photon path lengths
that can overpass 300 transport mean free paths. Such a performance opens new
possibilities for biomedical optics applications.Comment: 12 pages, 3 figure
Time-resolved diffusing wave spectroscopy applied to dynamic heterogeneity imaging
We report in this paper what is to our knowledge the first observation of a
time-resolved diffusing wave spectroscopy signal recorded by transillumination
through a thick turbid medium: the DWS signal is measured for a fixed photon
transit time, which opens the possibility of improving the spatial resolution.
This technique could find biomedical applications, especially in mammography.Comment: 9 pages, 4 figure
Perceptual and Functional Antecedents of Local Residents' Support-for-Tourism: Findings of a Study in Hanoi, Vietnam
An alternative role of FoF1-ATP synthase in Escherichia coli: synthesis of thiamine triphosphate
In E. coli, thiamine triphosphate (ThTP), a putative signaling molecule, transiently accumulates in response to amino acid starvation. This accumulation requires the presence of an energy substrate yielding pyruvate. Here we show that in intact bacteria ThTP is synthesized from free thiamine diphosphate (ThDP) and Pi, the reaction being energized by the proton-motive force (Dp) generated by the respiratory chain. ThTP production is suppressed in strains carrying mutations in F1 or a deletion of the atp operon. Transformation with a plasmid encoding the whole atp operon fully restored ThTP production, highlighting the requirement for FoF1-ATP synthase in ThTP synthesis. Our results show that, under specific conditions of nutritional downshift, FoF1-ATP synthase catalyzes the synthesis of ThTP, rather than ATP, through a highly regulated process requiring pyruvate oxidation. Moreover, this chemiosmotic mechanism for ThTP production is conserved from E. coli to mammalian brain mitochondria